Skip to Main content Skip to Navigation
Theses

Complexation d'actinides (III, V et VI) par des ligands polyaminocarboxyliques

Abstract : The behaviour of actinides in the environment (in the surroundings of uranium miningsites, waste storage or contaminated sites) depends on the interaction of these elements with theorganic ligands present in these different systems. The interactions of actinides withpolyfunctional organic ligands could trap the element or inversely, favour their migration.In this work, the behaviour of actinides (III, V and VI) in aqueous solution was studied in thepresence of two polyaminocarboxylic ligands: nitrilotriacetic acid (NTA) and iminodiaceticacid (IDA).The study of the complexation of pentavalent protactinium by NTA and IDA was conductedaccording to a dual approach. A thermodynamic study carried out by liquid-liquid extraction inthe system TTA/Toluene/HClO4/NaClO4/Pa(V)/ligand, with protactinium at tracer scale (C233Pa< 10−10 M), has been implemented in order to determine the stoichiometry, the mean charge ofcomplexes and the associated formation constants. A structural approach with protactiniumin weighable quantity (C231Pa≈ 10−3 M) was conducted in order to determine the coordination geometry of complexes and interatomic distances.The variations of the distribution coefficient D of Pa(V) as a function of nitrilotriacetateconcentration enabled to determine that the maximum stoichiometry for the Pa-NTA and Pa-IDA systems is 2. For the Pa-NTA system, the two successive complexes predominant in theaqueous phase are a neutral species for (1:1) complex PaO(NTA) and charge -3 for the (1:2)which may correspond to PaO(NTA) -:R. In addition, Capillary Electrophoresis InductivelyCoupled Plasma Mass Spectrometry experiments have been performed to confirm the charge (-3) for the maximum stoichiometry complex. For the Pa-IDA system, the results have shownthe successive formation of two positive complexes PaO(IDA)3+ and PaO(IDA)+2. Optimized structures of Pa-NTA and Pa-IDA complexes were established using DFT or molecular dynamics calculations.The complexation of trivalent (Am and Cf) and hexavalent (Np and Pu) actinides with IDA was performed by Capillary Electrophoresis coupled with Inductively Coupled Mass Spectrometry(CE-ICP-MS). The variations of overall electrophoresis mobility of actinides species as function of CIDA2 allow the determination of the formation constants of actinides IDAcomplexes. The formation constants of complexes with (1:1) stoichiometry are reported forAm(III) and Cf(III). Concerning the complexes Np(VI) and Pu(VI) with iminodiacetic acid,formation constants of (1:1) and (1:2) stoichiometry complexes were determined
Complete list of metadatas

Cited literature [164 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-01983425
Contributor : Abes Star :  Contact
Submitted on : Wednesday, January 16, 2019 - 2:05:14 PM
Last modification on : Wednesday, October 14, 2020 - 4:00:20 AM

File

72426_LUCHINI_2018_diffusion.p...
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-01983425, version 1

Collections

Citation

Coralie Luchini. Complexation d'actinides (III, V et VI) par des ligands polyaminocarboxyliques. Chimie analytique. Université Paris-Saclay, 2018. Français. ⟨NNT : 2018SACLS328⟩. ⟨tel-01983425⟩

Share

Metrics

Record views

256

Files downloads

291